diff -r d2b277cb948e -r 6ae063fd27dc tests/quadrilaterals.py
--- a/tests/quadrilaterals.py	Mon Jun 24 10:13:13 2019 +0300
+++ b/tests/quadrilaterals.py	Mon Jun 24 10:16:36 2019 +0300
@@ -84,6 +84,7 @@
             for a, b, c in pairs(element.geometry.vertices, count = 3):
                 if cross_product(b - a, c - a).length() < 1e-5:
                     yield report_problem('collinear', bad_object = element)
+                    break
 
 @problem_type('hairline-polygon',
     severity = 'warning',